I get a creak in my R/SR bottom brackets about every 12 months. Usually summer, and only under load. It's slightly annoying but always responds to them being taken down, cleaned, relubed & re-loctited... But I can't say why they creak.Well, that time rolled around last night and I took them both down. No dirt, all clean, Hirth screws tight. Still wondering what causes the problem. I had the Hirth coupling screw adapter in the crank when I dropped the whole thing on the garage floor. I discovered that the Hirth coupling screw comes out and lo and behold - is covered with oxidation, and a bit of old loctite mixed with grime. Quick brush with the Dremel and back together - creaks are gone. It's probably been the screw and the washer all along.

Interesting. I'm on Centaur square taper and have had similar creaking some years, like yourself when the hotter days come. Usually I have just removed the cranks and re- seated them. Next time I will completely clean threads and all.

I've always cleaned the threads, but never taken the screw out of the drive side crank to do it. I always thought it was not removable but the sharp knock saw to that!The oxidation was inside the drive side axle where the screw seats into the Hirth. Open to the elements so a prime spot for attracting rubbish.

biker jk wrote:Sounds like a design fault. The Shimano system is better.

Hmm - given that the Hirth coupling is what is used in a jet turbine, and Campagnolo use one thread where Shimano uses four, I'd say the engineering is in Campagnolo's favour. In the word of one of my mechanical engineering mates "that's ridiculously over-engineered".

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